The Libyan crisis is set to dominate the agenda of NATO foreign ministers' gathering in Berlin on Thursday and Friday, amid rising fears that the alliance-led military campaign may face long stalemate.

Foreign ministers from 28 NATO countries, along with non-NATO contributors to the operation of "Unified Protector", will try to find ways to end the Libyan conflicts Thursday, some two weeks after the alliance assumed full control of the campaign from the United States following days of hard bargaining.

However, new rifts have emerged within the alliance as French Foreign Minister Alain Juppe and his British counterpart William Hague on Tuesday publicly pressed their NATO allies to step up air raids in Libya and provide more ground attack aircraft.

In addition, the leaders of France and Britain will hold an unscheduled summit in Paris to discuss the Libyan crisis Wednesday, just on the eve of NATO's meeting, which is seen as a sign of discord.

French officials have also called for the U.S., Italy, Spain, the Netherlands and Sweden to enhance their efforts in the campaign.

The U.S. has withdrawn its aircraft from conducting airstrikes against Libyan leader Muammar Gaddafi's ground forces, leaving NATO short of ground attack aircraft. Several European countries also put restrictions on the use of their planes.

NATO Secretary General Anders Fogh Rasmussen Wednesday defended the alliance's performance in Libya while attending the Contact Group Meeting on Libya in the Qatari capital of Doha.

"I don't agree with (the description of) NATO being slow, we have kept a very high operational tempo...Our operations will end when there is no longer a threat to civilians on the ground." Rasmussen said.

The NATO chief have denied suggestions by some allies, including arming rebel fighters and deploying ground troops in Libya, saying the alliance had not considered "more robust measures."

Analysts said that despite the NATO-led aerial campaign, which do help the rebel fighters on the ground, Gaddafi has shown no signs of stepping down, leaving the endgame of the operation elusive.

During the Berlin talks, NATO foreign ministers will also discuss the ISAF mission in Afghanistan and NATO-Russia ties.

Under mounting domestic pressure, NATO countries are eager to pull their troops out of Afghanistan and want to complete the transition process in Afghanistan by the end of 2014.

Though the Afghan government has announced the first batch of provinces and cities, which are set to be taken over by Afghan forces, the transition process will not be proved easy as many hurdles exist, including lack of capacity of Afghan soldiers and police, resilient Taliban militants.

On Friday, NATO foreign ministers and their Russian counterpart Sergei Lavrov will focus on the cooperation on Afghanitan and the European missile defense.